Battery help

Discussion in 'Motorhome Chat' started by dave jm, May 12, 2010.

  1. dave jm

    dave jm Read Only Funster

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    System panel in m/h shows 13.7/8 when engine is running on hab and main battery...charger working but never gets above this figure even after a longish run or on hookup for 2/3 days....Question.. should it go higher??
    When in storage for say 2.5-3 weeks main battery drops to 11.8/9...The only drainage i have found is 0.60 from the leisure battery this is gas detector and flashing red light on in built satnav/radio/cd player..would this help to keep the cab battery up??>>http://www.maplin.co.uk/Module.aspx?ModuleNo=217850 .....Dave:thumb:
     
  2. bushman51

    bushman51 Read Only Funster

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    Not an answer from a professional, just from an experienced camper: 13.8 V seem fine, whereas if you charged your battery with a solar panel, the voltage would go up to 14.3 or even higher (depending on the regulator). Topping up your battery with the small device you point to can't work in my eyes, I suggest to install a proper sized solar panel (80 - 150 W).
     
  3. dave jm

    dave jm Read Only Funster

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    Thanks on reply...solar panal would not help as m/h is stored undercover with just the bonnet and windscreen poking out...this is why maybe this solar panel in the window would help the drain:thumb:...Dave
     
  4. bushman51

    bushman51 Read Only Funster

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    I don't think such a small panel can make up the loss you encounter. But as I said, this is only the opinion of a non-professional, somebody else might know better.
     
  5. dave jm

    dave jm Read Only Funster

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    Pappajohn have you gone to sleep..there's a question for you
     
  6. pappajohn

    pappajohn Funster Life Member

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    hi dave, sorry mate, been out all evening.

    my opinion.

    No. it aint big enough.

    12watt will give, in a perfect world, 1amp....in reality it will be nearer 600ma at most...and only when the suns shining strongly on it, say 6hrs a day.

    you appear to have a drain of 60ma per hour...24hrs per day.

    BUT during the 6hrs of sun you are taking 60ma of the available 600ma charge to power the sat/radio/alarm leaving 540ma to charge the battery.

    540ma X 6hr day = 3.24ah going in.
    60ma X 24hr day = 1.44ah coming out.

    Great....1.8ah of charge going in per 6hrs of sun.....but the sun dont shine every day and for the days it dont shine you have to make up the 3.24ah charge you lose on those days...plus the 1.44ah drain for each day..... on the days the sun does shine.

    i reckon, to keep on top of it, you need a 50w panel to cover the sunless, no charge, days.

    bet you wish you'd never asked...dont you?:Rofl1:
     
  7. gazz

    gazz Formerly "gazznhelz"

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    if its got a caravan type charger in it, then 13.8 is all youll get i'm afraid, which isnt really enough to properly charge a lead acid battery.

    worried about the 13.8 from the alternator tho, should really be nearer 14.4, have you tried revving the engine a bit whilst looking at the panel?
    tho some older alternators did put out 13.8 volts, most modern ones put out 14.4 or so,

    tho if you have a split charge diode instead of a relay, that could be where the 0.6 volts is missing, but motorhomes dont usually use diodes, plus you said you get the same reading on the engine battery from the alternator.

    for a mains charger, if you want to camp off shore power, then you really need a proper 3 stage charger,
    assuming a single 110ah leisure battery, then a 20 amp charger will be more than enough,
    this will put in 20 amps of charge in the first stage (called bulk) whilst the voltage climbs to 14.4 (some chargers you can set to higher, 14.6 or 14.8 being the best, but you will need to top the battery up occasionaly, as high rates of charge cause it to gas, this is a good thing as the gas bubbles stir up the electrolyte)

    when the uppper voltage is reached, the charger switches to the 2nd stage, this is the absorbtion stage and is the most importiant, the voltage will be held at the high rate, but the current allowed to fall as the battery it charged fully, this can take hours to do, but can put the final 20% of charge into the battery other chargers cant,

    when the current falls to a set level, usually 4 amps or so, the charger switches into float mode, the final stage,
    this drops the voltage to 13.8 or below, as this is the voltage at wchich a battery needs to be over to get it to gas, and the current is what ever is needed, so when drawing power, you can go upto 20 amps and the charger will provide the power, go over and the charger should go back into absorbtion mode,

    of course if you use the motorhome like a caravan, i.e. always on campsites with electric hook up, then dont worry, keep the system as it is, you wont see the benefit of that extra 20% of capacity (which is actually more in terms of available powe, due to peurketts law, but that is bloomin complicated, and i prolly spelt it wrong)


    i do assume you ment the leisure battery is the one that goes flat? as your last paragraff inst too clear to me (but htne again i'm thick, so prolly readin it wrong)

    but the 0.60 drain from the gas detector.... can you turn it off when in storage? and what did you use to get that figure?
    just wondering if it's from a multimeter, or the panel, as it could be saying theres a 600 milliamp drain, (i'd expect to see 0.06 for a 60 milliamp drain, but then again over half an amp for a gas detector is bloomin high, mine dosent even pull that when sounding)

    the flashing led on the radio wont pull much, but what will is the internal memory, modern radios, especialy the all singing and dancing one like you have, pull a lot of standby power,

    that's where i'm confoozled you see, the gas detector should run off the leisure battery, the cab radio off the engine battery, and the 2 batteries should be automaticaly disconnected unless the alternator is charging them,

    hence only one of them should be going down. anyhoo, i'll stop waffeling now as im confusing my self,
     
  8. dave jm

    dave jm Read Only Funster

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    You can say that again:cry:but i did manage to get to grips with it(to a fashion)...BUT then i read GAZZNHELZ reply and went into a complete state of anxiety ..it took 9 injections and 11 tablets and still ended up in CONFUSED.COM:Rofl1:...Thanks to you both:thumb:...Dave
     
  9. dazzer

    dazzer Read Only Funster

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    Just disconnect the hab battery when the van isnt used....problem solved :thumb:
     
  10. VMax666

    VMax666 Read Only Funster

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    Dave, Almost certain to be the radio. If you have the code for the radio you can always disconnect it ( I put mine on the leisure battery, and put a switch to the main feed) . You will probably find 2 power inputs, 1 to the ignition switch, 1 to the battery. Trouble is if it is a factory fit you would have to pull it out to find the block connector with all the feeds.
    VMax
     
  11. pappajohn

    pappajohn Funster Life Member

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    agreed Gazz.
    i would also expect to see 0.06 for 60ma and 0.60 for 600ma which does sound very high for a radio memory and gas alarm.
    i guessed it was a typo or a miss reading of the meter so settled for 60ma
    600ma drain will be 14.4amps drain per day :Eeek:
    my toad radio uses 9ma on memory and 197ma when ignition turned on but radio off.
     
  12. gazz

    gazz Formerly "gazznhelz"

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    i've still got my touch i see :)

    i was going to suggest you isolate the cab battery when not in use, i do that on my motorhome, not due to current drain problems but for an antitheft measure,

    all i loose when i isolate the cab battery is the memory for the radio stations, BUT on those modern radios that have everything but a goblin teasmaid built into them, you may loose a lot more than just the preset station memory,

    with the sat nav being built in you may loose poi's, trip data and so on, and it may take ages to get a sat lock when turned back on, handheld gps's do that if you leave them flat for while, they keep a memory of where the sats should be in the sky when powered off, so know where to look so to speak when powered up again, but if they loose their memory, they need to start from scratch, and it can take 10 to 15 minutes on some to get a lock,


    personaly i would say if that maplins solar panel jobbie is cheap enough for you, get it,

    yes i agree they are pretty naff, but that's mainly due to how they are marketed, so many people have been led to believe they can spend 20 quid on a solar panel 1 foot by 4 inches in size, and it will solve all their energy needs forever, thats all down to how the marketing people word the ads,
    i've even had people laugh at me when i told them about my solar array (375watts worth over 3 panels that are about 2 foot by 5 foot each, and cost 350 quid each panel (or 800 quid each if you were to buy at a motorhome show :)

    they rekon they can do that same with a 30 quid battery saver panel they saw advertized in the daily mail, and just wont believe otherwise... untill they try it of course.

    but that little panel may just help your situation out, like pappajohn says, in this country it wont keep the battery full all the time, too many overcast or rainy days, not enough sunlight hours, but it 'should' help slow down the discharge rate, maybe allowing you 6 weeks of unused time instead of 3.
     
  13. VMax666

    VMax666 Read Only Funster

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    Just checked some figures from when I had a problem with the engine battery going down after a few weeks. The radio/cd had been wired Switch Live and Permanent Live both direct to the engine battery to use the radio with engine off. The drain was .25amp. Disconnecting the Switch Live feed from the Permanent Live feed resulted in a draw of only 0.01amp. Rewired to a feed from the leisure battery with a throw switch on the Switch Live feed, radio stations retained, no loss from engine battery. Sorted:thumb:
    The radio draws 0.6 - 0.75amp when on, not surprising people flatten batteries with constant use. VMax
     
  14. dave jm

    dave jm Read Only Funster

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    Just phoned the company that fitted the Kenwood system in and they have wired it to the hab battery with on/off switch on dashboard.The 0.6amp drain is from the hab side according to the panel above door but will not show drain from cab..had the cab battery checked..no drain...but still the battery loses after about 3 weeks...Dave
     
  15. VMax666

    VMax666 Read Only Funster

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    Its knackered.:cry: Sorry about the technical terms,:Laughing: VMax
    PS Has it got a fancy alarm system?
     
  16. dave jm

    dave jm Read Only Funster

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    Had cab battery checked by 2 seperate companys...one small and the other a Fiat main agent..both said OK:cry:
    Dont leave it alarmed when it is in the secure lock up...but their is a tracker on it(by previous owner)..never changed name to me as they wanted an arm and leg to change it...would that have anything to do with the battery ??...Dave
     
  17. VMax666

    VMax666 Read Only Funster

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    Dave, If by not alarmed you mean you haven't pressed the remote, the alarm is still "On" as in a TV in standby. It is a radio receiver waiting for a signal, and will still be drawing current as will the tracker. The biggest profit maker in the motorcycle job is selling new batteries in April after a winter of inactivity, the batteries just die because of the alarm that they had fit for insurance.:Smile: There was extra profit selling an Optimate to save another £80 next winter. Stick a meter between the battery and the alarm to find out how much. Some alarms go into sleep mode to stop this, but I not aware of car alarms that do so.
    VMax
     
  18. dave jm

    dave jm Read Only Funster

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    I think that bloody thing is draining..problem is who knows where they fit the thing in the first place...probably the best solution is disconnect the earh side on the cab battery then leave it for a couple of weeks then put a meter on it and see what it reads then...Dave
     
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